1. Field of the Invention
The present invention relates to electronic monitoring systems, and in particular to systems for electronically monitoring scaling in an apparatus for heating and/or evaporating a liquid.
2. Discussion of the Related Art
Numerous systems of this type are known in the prior art, wherein either temperature changes, as they result from measuring the temperature and partially their time curve, or current changes, particularly with respect to galvanically separated current supplies to a heating element, are acquired.
For example, German Patent 42 18 440 A1 discloses a coffee machine or tea machine comprising a flow heater, which is composed of a water-carrying flow pipe and a heating aggregate, and a scaling indicator, whereby the scaling indicator has an indicator lamp arranged in a housing wall, whereby said indicator lamp is switched on given a specific temperature increase in the surrounding area of the flow heater as a result of scaling of the flow pipe.
German Patent 28 39 062 C2 discloses a further device for a flow heater, whereby the heating element has respectively individually galvanically separated current supplies in the area of the liquid input and the liquid output and whereby a circuit is provided with which a relative current change in these current supplies is used for these two areas as signal voltage for an indicator.
German Patent 26 52 399 A1 discloses an electrical coffee machine having a scaling indicator, which has a water level measuring device or water level adjusting device coupled with a timer. This scaling indicator requires great switching outlay.
German Patent 28 43 655 A1 discloses a device for the communication of a specific scaling degree of hot-water apparatuses, particularly coffee machines, by using a measuring chamber having an admission through which at least a partial amount of the generated hot water is led into the measuring chamber, whereby this cannot be transferred to steam generators, wherein a hot-water outlet is not traversed during the operation of the steam generator.
Besides, numerous systems and methods for removing lime deposits in order to assure a perfectly operating device for heating and/or vaporizing a liquid are certainly known. For example, European Patent 0 383 327 B1 discloses a steam generator for a cooking device, such as a tabletop device or standalone device using hot-air and hot steam as a combination for the gastronomy, large kitchens or suchlike, with a water-filled boiling vessel comprising an automatically level-regulated water inlet, a steam outlet for automatically introducing hot steam as needed into the cooking area of the cooking device and a heating device operating in intervals, and a decalcification device comprising a water outlet means that is arranged close to the bottom and the sidewall of the boiling vessel for at least partially emptying the boiling vessel as needed in order to flush out lime particles that have flaked off and that have accumulated at the bottom of the boiling vessel. The water outlet device has a flush-out pump, which is automatically switched on in adjustable intervals dependent on the operating time and/or operating temperature of the heating device, while a flush-out stream of water, which can be switched on and off together with the flush-out pump, is arranged close to the bottom of the boiling vessel at a location close to the wall of the boiling vessel, whereby said location is essentially diametrically situated opposite the flush-out pump, so that lime particles accumulating at the bottom of the boiling vessel as a result of the intense currents and the forced transport are reliably flushed out by the flush-out pump.
Regulation of a level within a container is well known to someone skilled in the art via a level measurer or, respectively, a liquid level sensor, and also is described in European Patent 0 191 267 B1, which also discusses decalcification of a container by removing limestone.
Conventionally, decalcification is performed at regular intervals, which are based on statistic extrapolations of operating times and experimental values, without actual calcification conditions being considered.
It is an object of the present invention to simply and reliably monitor the scaling status of an apparatus for heating and/or evaporating a liquid.
It is a further object of the present invention to provide a flow meter that acquires a liquid flow rate and/or evaporation rate.
It is an additional object of the present invention to provide a flow meter as a pulse counter.
It is yet another object of the present invention to provide a first flow meter upstream of a container and/or a second flow meter downstream of the container.
It is another object of the invention to provide a signal that indicates the difference between a nominal filling volume and a desired filling volume determined from the nominal liquid level or the nominal filled-in quantity exceeds at least a specific threshold value.
It is yet a further object of the invention to provide a display unit, which receives the signal of the evaluation unit and outputs an optical and/or acoustic warning message dependent on the signal, in the form of illuminated symbols, when the evaluation unit and the display unit are integrally implemented.
It is still another object of the present invention to provide a decalcification process that can be automatically initiated via an evaluation unit.
It is still a further object of the present invention to provide an apparatus for heating and/or vaporizing a liquid having a steam generator, preferably for a cooking device.
It is still an additional object of the present invention to easily monitor changes in the filling volume of a container due to lime deposits in order to be able to indicate when decalcification must be carried out, and/or to have decalcification automatically carried out, as soon as necessary.
Further features and advantages of the invention derive from the following specification in which an exemplary embodiment of the invention is explained in greater detail.